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MATERIAL HANDLING—TRANSPORTATION OF SOLIDS
81
Formula (1)    K Where,
O.OTw
Formula (2)    Q = Q.Q7KW
K — Rated capacity of locomotive crane in tons,
Q = Capacity in tons per hour (average) based on filling and discharging
bucket 40 times per hour, and wf » Weight of material handled in pounds per cubic foot.
Example 1.—Desired size of locomotive crane required to handle 125 tons of material weighing 80 Ib. per cubic foot per hour.
K
125
0-07 X 80
= 22.32.    Use 20-ton locomotive crane.
Example 2.—Desired average capacity of 15-ton locomotive crane when handling loose material weighing 80 Ib. per cubic foot.
Q = 0 • 07 X 15 X 80 = 84 tons per hour.
Fuel Requirements.—Locomotive cranes are for the most part steam operated and on account of the intermittent nature of their operation average fuel consumption is the most reliable index of power requirements. With coal of average grade, the average fuel requirements for standard sizes of locomotive cranes are:
TABLE 3.—FUEL REQUIREMENTS OF LOCOMOTIVE CRANES
10-ton crane......    90 Ib. per hour       20-ton crane......  160 Ib. per hour
15-ton crane......  120 Ib. per hour       25-ton crane...... 200 Ib. per hour
30-ton crane...... 240 Ib. per hour
Labor.—The crews customarily required to operate locomotive cranes are shown in Table 4.
Incidental supplies required for operating locomotive cranes constitute a charge per day of from 0.3 to 0.4 ct. per ton rating of crane per hour, such charge including the expenses contracted for oil, grease, waste, etc. Ordinary wear and tear (replacing cables, etc.), adds to the cost of operation an average of from 0.4 to 0.6 ct. per ton rating of crane per hour, making a total for incidental expenses of from 0.7 to 1.0 ct. per ton rating per hour operation. The initial cost of a locomotive crane varies from between $400 and $500 per ton of rated capacity, the smaller cranes being proportionally the more expensive. The burden (fixed charges)—represented by interest on investment, taxes, insurance, obsolescence, etc.—will constitute a yearly charge totaling to about 16.5 per cent of the initial cost of crane.
The net cost of operating standard sizes of locomotive cranes consists of the expenses for fuel, labor, incidental expenses and burden, or net cost per ton,
TABLE 4
Size of crane,	Crow	
tons	Engineer	Helpers
10	1	1
15	1	1 or 2
20	1	2
25	I	2
30	1	2
(F + L_+ E)!3Mr B """""
Formula (3)